Field
Embodiments of the present disclosure generally relate to creating planar surfaces on substrates and on layers formed on substrates, including an apparatus for cleaning a polishing pad, and methods of using the same. More specifically, the present disclosure relates to chemical-mechanical polishing (CMP).
Description of the Related Art
In the fabrication of integrated circuits and other electronic devices, multiple layers of conducting, semiconducting, and dielectric materials are deposited on or removed from a surface of a substrate, such as a semiconductor substrate or a glass substrate. As layers of material are sequentially deposited on and removed from the substrate, the uppermost surface of the substrate may become non-planar and call for planarization and/or polishing before further lithographic patterning can be patterned thereon. Planarization and polishing are procedures where previously deposited material is removed from the feature side of a substrate to form a generally even, planar, or level surface. Planarization and polishing are useful in removing undesired surface topography and surface defects, such as rough surfaces, agglomerated materials, crystal lattice damage, scratches, and contaminated layers or materials. Planarization is also useful in forming features on a substrate by removing excess material which has been deposited to fill the features, and to provide an even surface for subsequent lithography-based patterning steps.
Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique which is useful in removing undesired surface topography, or in forming features on a substrate by removing excess deposited material used to fill the features and to provide an even or level surface for subsequent deposition and processing. In conventional CMP techniques, a substrate carrier or polishing head is mounted on a carrier assembly to position a substrate secured therein in contact with a polishing pad in a CMP apparatus. The carrier assembly provides a controllable pressure to the substrate against the polishing pad. The polishing pad is moved relative to the substrate by an external driving force. Thus, the CMP apparatus creates polishing or rubbing movement between the surface of the substrate and the polishing pad while dispersing a polishing composition, or slurry, to affect both chemical activity and mechanical activity. Relative motion is provided between the substrate and polishing surface to planarize the surface of the substrate in contact with the pad through one or a combination of a chemical, mechanical, or electrochemical process. The polishing pad has a precise shape to distribute the polishing fluid and contact the substrate. The polishing pad may be cleaned to remove debris which would otherwise collect upon the polishing pad and cause damage to substrates processed therewith and reduce the polishing pad life.
Conventional methods of cleaning may involve directing de-ionized water (DIW) spray against the polishing pad. The spray often causes slurry and debris to become deposited on the pad and thereby collect in undesirable locations resulting in substrate contamination or scratching of later-polished substrates. The spray may also create a mist or include the debris, which can accumulate in a manufacturing facility to reduce the overall cleanliness of the facility and scratch later-polished substrates. Reducing the velocity of the spray to better control the debris has the effect of reducing the effectiveness of the debris removal from the polishing pad.
What is needed in the art is a method and apparatus for improving the range of certain CMP processes. Specifically, what is needed is an improved method and apparatus for cleaning of the polishing pad by effectively removing debris which may minimize the potential to contaminate or scratch later-polished substrates.